where \(L_{m}\left( x\right) \equiv L_{m}^{0}\left( x\right)\)  stands for the \(m\) -order Laguerre polynomial \(L_{m}^{k}\)  for \(k=0\) . The polynomial \(L_{m}^{k}\)  are defined by [1]}, [2]}
\(L_{m}^{k}\left( x\right) =\sum _{l=0}^{m}\frac{\left( -1\right) ^{l}\left(m+k\right) !x^{l}}{l!\left( l+k\right) !\left( m-l\right) !}\) 
